Conventionally, illuminating devices capable of outputting planar light have been known and used as backlight units for illuminating a liquid crystal display panel of a liquid crystal display device. Examples of such illuminating devices for liquid crystal display devices include a direct-type illuminating device, a side-light-type illuminating device, and the like.
Incidentally, the direct-type illuminating device is one in which a light source is arranged to be directly under a liquid crystal display panel. On the other hand, the side-light-type illuminating device is one in which a light guide plate is arranged to be directly under a liquid crystal display panel, and a light source is arranged to face a predetermined side-end surface of the light guide plate (see, for example, Patent Document 1). In such a side-light-type illuminating device, light emitted from the light source is introduced into the light guide plate via the predetermined side-end surface of the light guide plate. Then, the light introduced into the light guide plate is converted to planar light to illuminate the liquid crystal display panel.
FIG. 7 is a diagram schematically showing an example of a conventional side-light-type illuminating device, and FIG. 8 is a diagram for illustrating the shape of a case member (a member in which a light source and a light guide plate are placed) used for the conventional side-light-type illuminating device shown in FIG. 7. The structure of the conventional side-light-type illuminating device will be described below with reference to FIGS. 7 and 8.
In the conventional side-light-type illuminating device, as shown in FIG. 7, a plurality of light emitting diode devices (LEDs) 101 are used as the light source. The plurality of LEDs 101 are built into a module by being mounted on a same flexible printed wiring board (FPC) 102, such that light emitting surfaces of the LEDs 101 face a predetermined side-end surface (a light incident surface) of a light guide plate 103. An optical sheet 104 is disposed at a front surface (a light exit surface) side of the light guide plate 103, and a reflection sheet 105 is disposed at a rear surface side of the light guide plate 103. These members (the LEDs 101, the FPC 102, the light guide plate 103, the optical sheet 104, and the reflection sheet 105) are attached to a case member 106 that is formed in a box shape.
The case member 106, as shown in FIGS. 7 and 8, has a bottom portion 106a, and side portions 106b formed to stand up from the periphery of the bottom portion 106a. A space at the side of an upper surface of the bottom portion 106a of the case member 106 and surrounded by the side portions 106b is a housing space in which the above-described members (the LEDs 101, the FPC 102, the light guide plate 103, the optical sheet 104, and the reflection sheet 105) are placed.
Outside the housing space (at the side opposite to the side of the upper surface of the bottom portion 106a of the case member 106), there is disposed a power supply board 107, which is electrically connected to the LEDs 101 that are located within the housing space. Specifically, in the case member 106, an opening portion 106c is formed in one of the side portions 106b that is located at the LEDs 101 side, and via the opening portion 106c formed in the case member 106, a connection terminal of the FPC 102 that is connected to the power supply board 107 is drawn out from the inside to the outside of the housing space. By the FPC 102 whose connection terminal is drawn out through the opening portion 106c of the case member 106, the LEDs 101 located in the housing space and the power supply board 107 located outside the housing space are electrically connected to each other.